1. Field of the Invention
The present invention relates to an optical disc, a video data editing apparatus, a computer-readable recording medium that stores an editing program, a reproduction apparatus for the optical disc, and a computer-readable recording medium that stores a reproduction program.
2. Description of the Background Art
Video editors in the film and broadcasting industries make full use of their skill and experience when editing the great variety of video productions that reach the market. While movie fans and home video makers may not possess such skill or experience, many are still inspired by professional editing to try video editing for themselves. This creates a demand for a domestic video editing apparatus that can perform advanced video editing while still being easy to use.
While video editing generally involves a variety of operations, domestic video editing apparatuses that are likely to appear on the market in the near future will especially require an advanced scene linking function. Such function links a number of scenes to form a single work.
When linking scenes using conventional domestic equipment, the user connects two video cassette recorders to form a dubbing system. The operations performed when linking scenes using this kind of dubbing system are described below.
FIG. 1A shows a video editing setup using video cassette recorders that are respectively capable of recording and playing back video signals. The setup of FIG. 1A includes the video cassette 301 that records the source video, the video cassette 302 for recording the editing result, and two video cassette recorders 303 and 304 for playing back and recording video images on the video cassettes 301 and 302. In this example, the user attempts to perform the editing operation shown in FIG. 1B using the setup of FIG. 1A.
FIG. 1B shows the relationship between the material to be edited and the editing result. In this example, the user plays back scene 505 that is located between time t5 and time t10 of the source material, scene 506 that is located between time t13 and t21, and scene 507 that is located between time t23 and t25 and attempts to produce and editing result that is only composed of these scenes.
With the setup of FIG. 1A, the user sets the video cassette 301 including the source material into the video cassette recorder 303 and the video cassette 302 for recording the editing result into the video cassette recorder 304.
After setting the video cassettes 301 and 302, the user presses the fast-forward button on the operation panel of the video cassette recorder 303 (as shown by {circle around (1)} in FIG. 1A) to search for the start of scene 505. Next, the user presses the play button on the operation panel of the video cassette recorder 303 (as shown by {circle around (2)} in FIG. 1A) to reproduce scene 505. At the same time, the user presses the record button on the operation panel of the video cassette recorder 304 (as shown by {circle around (3)} in FIG. 1A) to commence recording. When scene 505 has finished, the user stops the operation of both video cassette recorders 303 and 304. The user then fast-forwards the video cassette to the start of scene 506, and then simultaneously commences the playback by video cassette recorder 303 and the recording by video cassette recorder 304. After completing the above process for scenes 506 and 507, the user has the video cassette recorders 303 and 304 respectively rewind the video cassettes 301 and 302 to complete the editing operation.
If the scene linking operation described above could be performed with ease at the home, users would then be able to easily manage programs that have been recorded on a large number of magnetic tape cassettes.
A first problem with the video editing setup described above is that the source material and editing result need to be recorded on separate recording media, meaning that two video cassette recorders need to be used for playing back and recording the respective recording media. This greatly increases the scale of the video editing setup. Since video editing can only be performed in a place where it is possible to connect two video cassette recorders, this means that a large space is required to perform the editing operation.
A second problem with the video editing setup described above is that when the user wishes to perform a scene linking operation, the user has to repeat the processes of locating the start of the desired scene and reproducing all of the video images from the beginning to the end of the scene for each scene to be linked. Here, the larger the number of scenes to be linked, the greater the burden of locating the start of each scene and reproducing the scene, meaning that the complex operations end up taking a considerable amount of time.
When a professional editor performs scene linking, instead of producing the editing result in one attempt, it is common for the editor to repeatedly amend the scene linking order so that high-quality results can finally be achieved. When using a setup where locating the start and reproducing scenes takes so much trouble, it is very difficult to perform such repeated amendment of the scene linking order.
These problems can be thought of as being caused by the use of magnetic tape as the recording medium, so that improvements could be made by using a video editing setup that utilizes a recording medium which allows random access, such as a hard disc or phase change-type optical disc.
As one example, if an optical disc were used to store the editing material and the editing result could be stored on the same optical disc, video editing would then be possible using only one video data editing apparatus that uses an optical disc as a recording medium, thereby greatly reducing the scale of the editing equipment. However, if both the editing source material and editing result are stored on the same optical disc, there can be cases when the editing result ends up being overwritten over the editing source material. In such a case, if the editor later wishes to change the editing result, the source material will have been overwritten, meaning that the editor will not be able to redo the editing using the original source materials.
When the editing source materials are of great personal value, such as footage of a child's school entrance ceremony, a school sports day, a family holiday, or a graduation ceremony, the overwriting of the source materials denies the user the chance to watch such important events again, let alone the chance to re-edit them. If the recording medium has a capacity that is greater than double the size of the source materials, an editing operation could presumably be performed without overwriting the source materials. However, for phase-change optical discs that are the most advanced recording medium, the recording capacity is still only 2.6 GB on one side, so that it is not possible to record video images with a reproduction time of greater than two hours separately as source materials and editing results. Also, if the user wishes to create several intermediate versions and record these separately on the optical disc to allow the selection of the best one at a later date, a recording disc with three or four times the date size of the audio video data (data produced by multiplexing video data and audio data) will be required. It can therefore be readily understood that the storage capacity of a single disc is insufficient.
A third problem with the video editing setup described above is that the sections to be linked cannot be precisely indicated. When performing the editing shown in FIG. 1A, the user needs to press the play button of one video cassette recorder at the same time as the record button on the other video cassette recorder. If the user presses one of these buttons before the other, there is the problem that an undesired part will end up in the recording result, or that the editing result will not include the start of the desired part.